A variety of fan systems have been made and used over the years in a variety of contexts. For instance, various ceiling fans are disclosed in U.S. Pat. No. 7,284,960, entitled “Fan Blades,” issued Oct. 23, 2007; U.S. Pat. No. 6,244,821, entitled “Low Speed Cooling Fan,” issued Jun. 12, 2001; U.S. Pat. No. 6,939,108, entitled “Cooling Fan with Reinforced Blade,” issued Sep. 6, 2005; and U.S. Pat. No. D607,988, entitled “Ceiling Fan,” issued Jan. 12, 2010. The disclosures of each of those U.S. patents are incorporated by reference herein. Additional exemplary fans are disclosed in U.S. Pub. No. 2008/0008596, entitled “Fan Blades,” published Jan. 10, 2008; U.S. Pub. No. 2009/0208333, entitled “Ceiling Fan System with Brushless Motor,” published Aug. 20, 2009; and U.S. Provisional Patent App. No. 61/175,210, entitled “Ceiling Fan with Variable Blade Pitch and Variable Speed Control,” filed May 4, 2009, the disclosures of which are also incorporated by reference herein. It should be understood that teachings herein may be incorporated into any of the fans described in any of the above-referenced patents, publications, or patent applications.
A fan blade or airfoil may include one or more upper air fences and/or one or more lower air fences at any suitable position(s) along the length of the fan blade or airfoil. Merely exemplary air fences are described in U.S. Provisional Patent App. No. 61/248,158, entitled “Air Fence for Fan Blade,” filed Oct. 2, 2009, the disclosure of which is incorporated by reference herein. Alternatively, any other suitable type of component or feature may be positioned along the length of a fan blade or airfoil; or such components or features may simply be omitted.
The outer tip of a fan blade or airfoil may be finished by the addition of an aerodynamic tip or winglet. Merely exemplary winglets are described in U.S. Pat. No. 7,252,478, entitled “Fan Blade Modifications,” issued Aug. 7, 2007, the disclosure of which is incorporated by reference herein. Additional winglets are described in U.S. Pub. No. 2008/0014090, entitled “Cuffed Fan Blade Modifications,” published Jan. 17, 2008, filed Sep. 25, 2007, the disclosure of which is incorporated by reference herein. Still other exemplary winglets are described in U.S. Design Patent No. D587,799, entitled “Winglet for a Fan Blade,” issued Mar. 3, 2009, the disclosure of which is incorporated by reference herein. In some settings, such winglets may interrupt the outward flow of air at the tip of a fan blade, redirecting the flow to cause the air to pass over the fan blade in a perpendicular direction, and also ensuring that the entire air stream exits over the trailing edge of the fan blade and reducing tip vortex formation. In some settings, this may result in increased efficiency in operation in the region of the tip of the fan blade. In other variations, an angled extension may be added to a fan blade or airfoil, such as the angled airfoil extensions described in U.S. Pub. No. 2008/0213097, entitled “Angled Airfoil Extension for Fan Blade,” published Sep. 4, 2008, the disclosure of which is incorporated by reference herein. Other suitable structures that may be associated with an outer tip of an airfoil or fan blade will be apparent to those of ordinary skill in the art. Alternatively, the outer tip of an airfoil or fan blade may be simply closed (e.g., with a cap or otherwise, etc.), or may lack any similar structure at all.
The interface of a fan blade and a fan hub may also be provided in a variety of ways. For instance, an interface component is described in U.S. Pub. No. 2009/0081045, entitled “Aerodynamic Interface Component for Fan Blade,” published Mar. 26, 2009, the disclosure of which is incorporated by reference herein. Alternatively, the interface of a fan blade and a fan hub may include any other component or components, or may lack any similar structure at all.
Fans may also include a variety of mounting structures. For instance, a fan mounting structure is disclosed in U.S. Pub. No. 2009/0072108, entitled “Ceiling Fan with Angled Mounting,” published Mar. 19, 2009, the disclosure of which is incorporated herein. Of course, a fan need not be mounted to a ceiling or other overhead structure, and instead may be mounted to a wall or to the ground. For instance, a fan may be supported on the top of a post that extends upwardly from the ground. Alternatively, any other suitable mounting structures and/or mounting techniques may be used in conjunction with embodiments described herein.
It should also be understood that a fan may include sensors or other features that are used to control, at least in part, operation of a fan system. For instance, such fan systems are disclosed in U.S. Pub. No. 2009/0097975, entitled “Ceiling Fan with Concentric Stationary Tube and Power-Down Features,” published Apr. 16, 2009, the disclosure of which is incorporated by reference herein; U.S. Pub. No. 2009/0162197, entitled “Automatic Control System and Method to Minimize Oscillation in Ceiling Fans,” published Jun. 25, 2009, the disclosure of which is incorporated by reference herein; WIPO Pub. No. WO/2009/100052, entitled “Automatic Control System for Ceiling Fan Based on Temperature Differentials,” published Aug. 13, 2009, the disclosure of which is incorporated by reference herein; and U.S. Provisional Patent App. No. 61/165,582, entitled “Fan with Impact Avoidance System Using Infrared,” filed Apr. 1, 2009, the disclosure of which is incorporated by reference herein. Alternatively, any other suitable control systems/features may be used in conjunction with embodiments described herein.
While many versions of the fans disclosed in the above-cited patents and patent applications are configured to be mounted to a ceiling, such as to provide downward and/or outward airflow, fans may alternatively be mounted to a floor, wall, upright structure, or other structure, and may be positioned at a variety of different locations and orientations. Fans may thus be configured to provide airflow in a generally upward or horizontal direction (in addition to or in lieu of a downward direction). In any such case, the fan may be configured to provide a generally axial flow of air.
In some settings, the ability of an axial flow fan to propel air over a long distance along the axis of the fan may be enhanced by the provision of a cylindrical shroud closely fitted around the circle defined by the tips of the blades of the fan. In some settings, the efficiency of this combination may increase as the diameter of the inner surface of the cylindrical shroud approaches the diameter of the circle of the fan blade tips. However, unavoidable variations in manufacturing materials and processes may make it necessary to allow a degree of clearance between the blade tips and the shroud to prevent them from coming into contact with one another in operation.
While a variety of fans and fan systems have been made and used, it is believed that no one prior to the inventors has made or used a fan system as described herein.
The drawings are not intended to be limiting in any way, and it is contemplated that various embodiments of the invention may be carried out in a variety of other ways, including those not necessarily depicted in the drawings. The accompanying drawings incorporated in and forming a part of the specification illustrate several aspects of the present invention, and together with the description serve to explain the principles of the invention; it being understood, however, that this invention is not limited to the precise arrangements shown.